Outphasing, or linear amplification with nonlinear components (LINC), allows input signals to be amplified by highly efficient nonlinear power amplifiers operating at or near saturation. Each variable-envelope input signal is separated into two constant-envelope component signals. These constant-envelope signals can be processed using a chain of analog components including mixers or amplifiers that have nonlinear input-output characteristics. The two constant-envelope signals are then combined using an analog combiner to create an amplified replica of the original signal. However, due to physical differences in the analog components as well as the frequency response of the analog combiner, the amplified output signal is not a perfect reconstruction of the input signal. Indeed, these analog components may combine to introduce linear distortions and multiple spectral impurities into the output signal.
Conventionally, nonlinear analog or digital pre-distortion (DPD) approaches are applied to decrease nonlinear signal distortion of the signals going through the analog signal chain. Analog pre-distortion has very limited performance, while DPD is very complex and inefficient. Perfect linearizations are virtually impossible. DPD's complexity is manifested in complex algorithms, requiring constant updates and additional hardware in the form of feedback loops. Moreover, due to complex algorithms, a significant amount of power is consumed in digital signal processor (DSP) operations, field programmable gate array (FPGA) operations, application-specific integrated circuit (ASIC) operations, or other integrated circuit operations, lowering overall system efficiency. These efficiency losses are purely and directly converted to heat which is virtually impossible to recycle.
The subject matter claimed herein is not limited to embodiments that solve any disadvantages or that operate only in environments such as those described above. Rather, this background is only provided to illustrate one exemplary technology area where some embodiments described herein may be practiced.